See Venus Bid Crescent Moon Farewell Early Thursday

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Early-bird stargazers will have rise early Thursday (Jan. 10) to
catch sight of the two brightest objects in the night sky — Venus
and the moon — engaged in a final pre-dawn dance.

To catch the celestial sight, set your alarm clock to ring one
hour before sunrise, then quickly head outside. Make sure you go
to a viewing site where your east-southeast sky is free of any
obstructions such as buildings or trees, since what you’re
attempting to see will be poised low above the horizon.

You’ll be looking for the brilliant
planet Venus, and hovering only just above and to its left
will be a hairline crescent moon, just 2-percent illuminated and
about 32 hours before reaching its new phase. Since the moon
became a morning fixture, this will mark the sixth time that it
has gotten together with Venus to form an eye-catching
configuration.

The moon is very close to us, only 224,000 miles (360,000
kilometers) distant, and lit from behind by the sun. Venus, on
the other hand, is on the far side of its orbit, on the far side
of the sun, 14,724,000 miles (23,696,000 km) away. Because it is
on the far side of the sun, it is almost fully illuminated by the
sun. In a telescope magnifying 160 times it appears as big as the
moon does to our naked eye, and it almost resembles a full
moon in its illumination. [ Stargazers'
Night Sky Photos for January ]

Unfortunately, this will be the last of such Venus-moon
spectacles for some time.

Venus has been a bright morning "star" since it emerged into view
shortly after its dramatic
transit across the face of the sun late last spring, but now
it's finally on its way out. Actually, Venus has slowly been
getting lower in the dawn sky for the last four months.

In January, this dazzling orb doesn't even rise until morning
twilight is under way, and it is only about 10 degrees up in the
sky — the equivalent of your clenched fist held at arm’s length —
by the time it fades away in the brightening morning sky. But
Venus' great brightness still renders it easily visible in the
east-southeast until just before sunrise.

The sooner you look for Venus this month, the better: By month's
end the planet won't appear over the horizon until after
mid-twilight, preceding the sun into the sky by only about 40
minutes.

Although Venus is still three months from superior conjunction
with the sun, the fact that it is placed well south of the
celestial equator keeps it very low as seen from mid-northern
latitudes. As it draws closer to the sun, Venus will drop deeper
into the bright morning twilight, eventually being rendered
invisible after the first week of February.

Venus will begin to re-emerge very low in the west-northwest
evening sky shortly after sunset during the second half of April.
From then on, it will spend the rest of 2013 getting
progressively higher and more prominent as an evening object. But
it won't be until nearly nine months from now, on Sept. 8, that
it will again have a close encounter with
the moon.

Editor's note: If you snap an amazing photo
of Venus and the moon, or any other night sky object,
that you'd like to share for a possible story or image
gallery, send photos, comments and your name and location to
managing editor Tariq Malik at spacephotos@space.com.

Joe Rao serves as an instructor and guest lecturer at New
York's Hayden Planetarium. He writes about astronomy for
TheNew YorkTimes and other publications, and he is
also an on-camera meteorologist for News 12 Westchester, New
York.Astronomer Geoff Gaherty of Starry Night Education
contributed to this report.